3-thienyl thioethers



Patented Dec. 15, 1953 UNITED STATES PATENT OFFICE 3'-THIENY LTHIOETHERS John W. Brooks, Wenonah, and- Sigmund J.

Lukasiewicz, Woodbury, N. .T.,.assignors to. Socony-VacuumOil Company,Incorporated, New York, N. Y;, a. corporation of New York No. Drawing.Original application November 22,

19.48, SeriaL No. 61,524. Divided. and thisv application June. 1,, 1951,Serial No. 229,536

where R is a (3-thienylthio)-alkylor' (di-3-thienylthio) -alkyl group.

As is well known to those familiar with the art, substantially all ofthe numerous fractions obtained from mineral oils and refined for theirvarious usesare susceptible to oxidation. The-susceptibility of an oilfraction to oxidation and the manner in which oxidation manifests itselfwithin the oil varies with the type and degree of refinement to whichthe oil has been subjected and with the conditions under which it isusedor tested. That is, the products formed in an. oil. fraction as aresult of oxidation and the degree to which they are formed depend onthe extent to which the various unstable constituents or constituentswhich may act as oxidation catalysts have been removed by refiningoperations and also upon the conditions of use;

The compounds of this invention greatly improve the oxidationcharacteristics of mineral oil fractions. It has been found that, by theaddition' of a 3-thienyl thioether having the above designated formulato a viscous mineral. oil fraction, the development of. undesirableproductsand properties, such as acid, sludge, discoloration. andcorrosiveness toward alloy-bearing metals, normally encountered underconditions of use, has been substantially inhibited.

The present compounds are suitably prepared by the action of anappropriate organic halide on B-thiophenethiol' in the presence of an.alkaline condensing agent such as alcoholic potassium hydroxide. Thechoice of organic halide reactant will be governed bygthe productdesired. In general, a halogenated parafiin containing at least" twohalogen atoms; not more than one of which is attached to the same carbonatom, will be used; In preparation of B-thienyl thioethers wherein R isa (3thienylthio)-alkyl group, a halogenated parafiln containing two ormore halogen atoms-attached to different carbon atoms will be employed.thioethers where R" is a (di-3-thienylthio)-alkyl group, a halogenatedparaffin containing three ormore halogen atoms attached to, difi'erentcar,- bon atoms will be employed. Typical ofvv the-organic halidesemployed in preparation of the in- In preparation, of 3'-thienyl the.ether at atmospheric. pressure.

stant compounds are. ethylene. chloride, 1,2,3-trl-' chloropropane, andtetramethylene chloride.

The above reaction. will usually be carried out with :a. molar ratio. ofthiophenethiol to organic halide of between about 2 to- 1 and about 4 to1*. Under the above described: conditions, the hydrogen of the mercaptogroup in the 3-thiophenethiol is replaced by thev radical to yield the.desired 3-thieny1 thioether. The aforementioned reactantof3-thiophenethiol may be: prepared by the-procedure described in Chem.Inds. 60, 593-5, 620- (1947') or by any other feasible-method.

The nature of the organic substituent group present in the 3-thienylthioethers described herein may be either a (mono-3-thienylthio)- alkylgroup or a (di-3-thienylthio)-alkyl group. Representative. of thecompounds of this invention are 1,2:-(di-3-thienylthio)-ethane; 1,2,3-(tri-3-thienylthio)-propane 1,4- (di-B-thienylthio) -butane', and the'like. This list, of course, is' not to-b'e construed as limiting sincethe present invention contemplates other 3'-thienyl thioethers'fallingwithin the scope of the above designated formula. Those skilled in theart will readily recognize various other (3-thienylthio)- alkyl3'-thienyl thioethers and (di-3-thienylthioialkyl 3-thienyl thioetherswhich may be synthesized according' to the above described procedures.

The preparation of the compounds of themesent invention may beillustrated by the following examples,v which are given by way ofillustration and not intended to be a limitation on the scope of theinvention.

Preparation. of 1323- ('tri-3-thienylthio) -prop1me.

Seventy-five grams (-0.5 mole) of 1,2,3-trichloropropane, 2033 grams(1.75 moles) of 3-thiophenethiol, and 150 milliliters of ethyl. alcoholwere added to a flask. A solution of 98 grams of potassium hydroxide(1.75 moles) in 125 milliliters. of. water and. 200 milliliters of ethylalcohol was slowly added to the flask. The tempera.- ture was.maintained at. about C. duringv this. addition. .At the endv of thistime, the resulting reaction mixture was diluted with water and.extracted with ethyl. ether. The ether solution. was then topped to apot temperature of 100 C..under one millimeter of mercury after firstremoving.

The result.-

ing product had a sulfur content of 41.8 per cent and a chlorine contentof 9.26 per cent. This reaction was incomplete, so 85 grams of thereaction product were mixed with 50 grams of 3-thiophenethioi and 20grams of potassium hydroxide in 200 milliliters of ethyl alcohol andheated to a temperature of 75 C. for a period of 2 hours. After washingwith water, drying and topping off the ethyl alcohol, 1,2,3-(tri-3-thienylthio)-propane was obtained, having a sulfur content of49.62 per cent, the theoretical sulfur content being 49.75 per cent.This compound is hereinafter referred to as Compound I.

EXAMPLE II Preparation of 1,2-(di-3thienylthio) -ethane Four hundred sixgrams (35 moles) of 3-thiophenethiol were placed in a flask and 196grams of potassium hydroxide (3.5 moles) in 450 cubic centimeters ofethyl alcohol and 200 cubic centimeters of water were added. Fourhundred forty-nine grams (1.5 moles) of ethylene chloride were added atsuch a rate to maintain the temperature in the range of 4550 C. Afterthe addition was completed, the reaction mixture was stirred at 75 C.for 5 hours. The resulting reaction mixture was Washed well with waterand 375 grams of white solid formed, representing a yield of 97 per centof 1,2-(di-3-thienylthio)- ethane, based on the weight of ethylenechloride. This material was recrystallized from cyclohexane and had amelting point of 54-55 C. and a sulfur content of 49.41 per cent, thetheoretical sulfur content being 49.62 per cent. This compound ishereinafter referred to as Compound II.

EXAMPLE III Preparation of 1,4-(di-3-thienylthio) -butane Four hundredsix grams (3.5 moles) of 3-thiophenethiol and 196 grams of potassiumhydroxide in 200 cubic centimeters of water and 350 cubic centimeters ofethyl alcohol were added to a flask. One hundred ninety-one grams (1.5moles) of tetramethylene chloride were added at such a rate that thetemperature was maintained in the range of 45-50 C. After the additionwas completed, the temperature of the mixture was raised to 75 C. andkept there for a period of 4 hours. The resulting reaction mixture waswashed well with water to give white, flaky crystals of1,4-(di-3-thienylthio)-butane in 87 per cent yield. This material wasrecrystallized from cyclohexane and had a melting point of 62-63 C. anda sulfur content of 44.05 per cent, the theoretical sulfur content being44.62 per cent. This compound is hereinafter referred to as CompoundIII.

The compounds of this invention have been found to be valuable asadditives in the stabilization of petroleum oil fractions, particularlyin inhibiting the development of those undesirable products andproperties such as acid, sludge, discoloration, and corrosiveness towardalloy-bearclng metals normally encountered upon conditions of use. Thus,it is well known that motor oils, especially those refined by certainsolventextraction methods, tend to oxidize when submitted to hightemperatures and to form products that are corrosive to metal bearings.This corrosive action may be quite severe with certain bearings, such asthose having the corrosion susceptibility of cadmium-silver alloys, andmay cause their failure within a comparatively short time. The followingtest was used to determine 4 the corrosive action of a motor oil on anautomobile rod bearing.

The oil used consisted of Pennsylvania neutral and residuum stocksseparately refined by means of chlorex and then blended to give an S. A.E. 20 motor oil with a specific gravity of 0.872, a flash point of 435F. and a Saybolt Universal viscosity of about 318 seconds at F. The oilwas tested by adding a section of a bearing containing a cadmium-silveralloy surface and weighing about 6 grams, and heating it to 175 C. for22 hours while a stream of air was bubbled against the surface of thehearing. The loss in weight of the bearing during this treatmentmeasures the amount of corrosion that has taken place. A sample of theoil containing a stabilizing compound of this invention was run at thesame time as a sample of the straight oil and the loss in weight of thebearing section in the inhibited oil can thus be compared directly withthe loss in the uninhibited oil. The results obtained in this testemploying minor proportions of the above described compounds asinhibitors are set forth in the following table:

1 Concentra- A second test to which an oil containing a minor proportionof the compounds of this invention was subjected consisted essentiallyof passing oxygen through a -gram sample of oil at a rate of 2 litersper hour for a period of 70 hours at a temperature of 250 F. andmeasuring the neutralization number of the oil at the end of the test.In this test, the base oil containing no additive developed aneutralization number of about 20. The following data indicate that thecompounds of this invention are effective in inhibiting the developmentof acidity in a mineral oil when the same is subjected to oxidationconditions as evidenced by the comparatively low neutralization numberof such oils at the completion of the above test. In each of the oilstested, 0.1 per cent by weight of a compound of this invention wasincorporated therein.

Neutralization None From the foregoing test results, it will be evi--dent that the S-thienyl thioethers of this invention are effectivestabilizing agents for petroleum lubricating oil fractions. The quantityof compound employed as stabilizer to inhibit the undesirable eifects ofoxidation in the oil may be varied, depending upon the character of theoil and the severity of the conditions to which it is exposed.Ordinarily, the compositions will be added to mineral oil fractions inan amount ranging from about 0.1 to about 4 per cent, but may be addedin amounts up to 10 per cent by weight in some instances.

This application is a division of co-pending ap- 5 p'lication SerialNumber 61,524, filed November 22, 1948, and issued as U. S. 2,577,566 onDecember 4, 1951, which, in turn, is a division of application SerialNumber 791,652, filed December 13, 1947, and issued as U. S. 2,480,832,on 5 September 6, 1949.

We claim:

1. As a new composition of matter, a 3-thieny1 thioether characterizedby the formula:

4. As a new composition of matter, 1,4-(di-3- thieny1thio)-butane,characterized by the formula:

5. As a, new composition of matter, 1,2,3-(tr1- 10 3-thieny1thio)-propane, characterized by the formula:

H H H S-g-Z-g-S U U JOHN W. BROOKS.

SIGMUND J. LUKASIEWICZ.

References Cited in the tile of this patent Steinkopf, Die Chemie DesThiophens," pp. 100-101, Steinkopf, Dresden, 1941, Edwards Bros.

25 Inc., Ann Arbor, Mich., 1944.

1. AS A NEW COMPOSITION OF MATTER, A 3-THIENYL THIOETHER CHARACTERIZEDBY THE FORMULA: